/*
 * WPA Supplicant / Crypto wrapper for LibTomCrypt (for internal TLSv1)
 * Copyright (c) 2005-2006, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"
#include <tomcrypt.h>

#include "common.h"
#include "crypto.h"

#ifndef mp_init_multi
#define mp_init_multi                ltc_init_multi
#define mp_clear_multi               ltc_deinit_multi
#define mp_unsigned_bin_size(a)      ltc_mp.unsigned_size(a)
#define mp_to_unsigned_bin(a, b)     ltc_mp.unsigned_write(a, b)
#define mp_read_unsigned_bin(a, b, c) ltc_mp.unsigned_read(a, b, c)
#define mp_exptmod(a,b,c,d)          ltc_mp.exptmod(a,b,c,d)
#endif


int md4_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
    hash_state md;
    size_t i;

    md4_init(&md);
    for (i = 0; i < num_elem; i++)
        md4_process(&md, addr[i], len[i]);
    md4_done(&md, mac);
    return 0;
}


void des_encrypt(const u8 *clear, const u8 *key, u8 *cypher)
{
    u8 pkey[8], next, tmp;
    int i;
    symmetric_key skey;

    /* Add parity bits to the key */
    next = 0;
    for (i = 0; i < 7; i++) {
        tmp = key[i];
        pkey[i] = (tmp >> i) | next | 1;
        next = tmp << (7 - i);
    }
    pkey[i] = next | 1;

    des_setup(pkey, 8, 0, &skey);
    des_ecb_encrypt(clear, cypher, &skey);
    des_done(&skey);
}


int md5_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
    hash_state md;
    size_t i;

    md5_init(&md);
    for (i = 0; i < num_elem; i++)
        md5_process(&md, addr[i], len[i]);
    md5_done(&md, mac);
    return 0;
}


int sha1_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
    hash_state md;
    size_t i;

    sha1_init(&md);
    for (i = 0; i < num_elem; i++)
        sha1_process(&md, addr[i], len[i]);
    sha1_done(&md, mac);
    return 0;
}


void * aes_encrypt_init(const u8 *key, size_t len)
{
    symmetric_key *skey;
    skey = os_malloc(sizeof(*skey));
    if (skey == NULL)
        return NULL;
    if (aes_setup(key, len, 0, skey) != CRYPT_OK) {
        os_free(skey);
        return NULL;
    }
    return skey;
}


void aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
{
    symmetric_key *skey = ctx;
    aes_ecb_encrypt(plain, crypt, skey);
}


void aes_encrypt_deinit(void *ctx)
{
    symmetric_key *skey = ctx;
    aes_done(skey);
    os_free(skey);
}


void * aes_decrypt_init(const u8 *key, size_t len)
{
    symmetric_key *skey;
    skey = os_malloc(sizeof(*skey));
    if (skey == NULL)
        return NULL;
    if (aes_setup(key, len, 0, skey) != CRYPT_OK) {
        os_free(skey);
        return NULL;
    }
    return skey;
}


void aes_decrypt(void *ctx, const u8 *crypt, u8 *plain)
{
    symmetric_key *skey = ctx;
    aes_ecb_encrypt(plain, (u8 *) crypt, skey);
}


void aes_decrypt_deinit(void *ctx)
{
    symmetric_key *skey = ctx;
    aes_done(skey);
    os_free(skey);
}


struct crypto_hash {
    enum crypto_hash_alg alg;
    int error;
    union {
        hash_state md;
        hmac_state hmac;
    } u;
};


struct crypto_hash * crypto_hash_init(enum crypto_hash_alg alg, const u8 *key,
        size_t key_len)
{
    struct crypto_hash *ctx;

    ctx = os_zalloc(sizeof(*ctx));
    if (ctx == NULL)
        return NULL;

    ctx->alg = alg;

    switch (alg) {
        case CRYPTO_HASH_ALG_MD5:
            if (md5_init(&ctx->u.md) != CRYPT_OK)
                goto fail;
            break;
        case CRYPTO_HASH_ALG_SHA1:
            if (sha1_init(&ctx->u.md) != CRYPT_OK)
                goto fail;
            break;
        case CRYPTO_HASH_ALG_HMAC_MD5:
            if (hmac_init(&ctx->u.hmac, find_hash("md5"), key, key_len) !=
                    CRYPT_OK)
                goto fail;
            break;
        case CRYPTO_HASH_ALG_HMAC_SHA1:
            if (hmac_init(&ctx->u.hmac, find_hash("sha1"), key, key_len) !=
                    CRYPT_OK)
                goto fail;
            break;
        default:
            goto fail;
    }

    return ctx;

fail:
    os_free(ctx);
    return NULL;
}

void crypto_hash_update(struct crypto_hash *ctx, const u8 *data, size_t len)
{
    if (ctx == NULL || ctx->error)
        return;

    switch (ctx->alg) {
        case CRYPTO_HASH_ALG_MD5:
            ctx->error = md5_process(&ctx->u.md, data, len) != CRYPT_OK;
            break;
        case CRYPTO_HASH_ALG_SHA1:
            ctx->error = sha1_process(&ctx->u.md, data, len) != CRYPT_OK;
            break;
        case CRYPTO_HASH_ALG_HMAC_MD5:
        case CRYPTO_HASH_ALG_HMAC_SHA1:
            ctx->error = hmac_process(&ctx->u.hmac, data, len) != CRYPT_OK;
            break;
    }
}


int crypto_hash_finish(struct crypto_hash *ctx, u8 *mac, size_t *len)
{
    int ret = 0;
    unsigned long clen;

    if (ctx == NULL)
        return -2;

    if (mac == NULL || len == NULL) {
        os_free(ctx);
        return 0;
    }

    if (ctx->error) {
        os_free(ctx);
        return -2;
    }

    switch (ctx->alg) {
        case CRYPTO_HASH_ALG_MD5:
            if (*len < 16) {
                *len = 16;
                os_free(ctx);
                return -1;
            }
            *len = 16;
            if (md5_done(&ctx->u.md, mac) != CRYPT_OK)
                ret = -2;
            break;
        case CRYPTO_HASH_ALG_SHA1:
            if (*len < 20) {
                *len = 20;
                os_free(ctx);
                return -1;
            }
            *len = 20;
            if (sha1_done(&ctx->u.md, mac) != CRYPT_OK)
                ret = -2;
            break;
        case CRYPTO_HASH_ALG_HMAC_SHA1:
            if (*len < 20) {
                *len = 20;
                os_free(ctx);
                return -1;
            }
            /* continue */
        case CRYPTO_HASH_ALG_HMAC_MD5:
            if (*len < 16) {
                *len = 16;
                os_free(ctx);
                return -1;
            }
            clen = *len;
            if (hmac_done(&ctx->u.hmac, mac, &clen) != CRYPT_OK) {
                os_free(ctx);
                return -1;
            }
            *len = clen;
            break;
        default:
            ret = -2;
            break;
    }

    os_free(ctx);

    return ret;
}


struct crypto_cipher {
    int rc4;
    union {
        symmetric_CBC cbc;
        struct {
            size_t used_bytes;
            u8 key[16];
            size_t keylen;
        } rc4;
    } u;
};


struct crypto_cipher * crypto_cipher_init(enum crypto_cipher_alg alg,
        const u8 *iv, const u8 *key,
        size_t key_len)
{	
    struct crypto_cipher *ctx;
    int idx, res, rc4 = 0;

    switch (alg) {
        case CRYPTO_CIPHER_ALG_AES:
            idx = find_cipher("aes");
            break;
        case CRYPTO_CIPHER_ALG_3DES:
            idx = find_cipher("3des");
            break;
        case CRYPTO_CIPHER_ALG_DES:
            idx = find_cipher("des");
            break;
        case CRYPTO_CIPHER_ALG_RC2:
            idx = find_cipher("rc2");
            break;
        case CRYPTO_CIPHER_ALG_RC4:
            idx = -1;
            rc4 = 1;
            break;
        default:
            return NULL;
    }

    ctx = os_zalloc(sizeof(*ctx));
    if (ctx == NULL)
        return NULL;

    if (rc4) {
        ctx->rc4 = 1;
        if (key_len > sizeof(ctx->u.rc4.key)) {
            os_free(ctx);
            return NULL;
        }
        ctx->u.rc4.keylen = key_len;
        os_memcpy(ctx->u.rc4.key, key, key_len);
    } else {
        res = cbc_start(idx, iv, key, key_len, 0, &ctx->u.cbc);
        if (res != CRYPT_OK) {
            wpa_printf(MSG_DEBUG, "LibTomCrypt: Cipher start "
                    "failed: %s", error_to_string(res));
            os_free(ctx);
            return NULL;
        }
    }

    return ctx;
}

int crypto_cipher_encrypt(struct crypto_cipher *ctx, const u8 *plain,
        u8 *crypt, size_t len)
{
    int res;

    if (ctx->rc4) {
        if (plain != crypt)
            os_memcpy(crypt, plain, len);
        rc4_skip(ctx->u.rc4.key, ctx->u.rc4.keylen,
                ctx->u.rc4.used_bytes, crypt, len);
        ctx->u.rc4.used_bytes += len;
        return 0;
    }

    res = cbc_encrypt(plain, crypt, len, &ctx->u.cbc);
    if (res != CRYPT_OK) {
        wpa_printf(MSG_DEBUG, "LibTomCrypt: CBC encryption "
                "failed: %s", error_to_string(res));
        return -1;
    }
    return 0;
}


int crypto_cipher_decrypt(struct crypto_cipher *ctx, const u8 *crypt,
        u8 *plain, size_t len)
{
    int res;

    if (ctx->rc4) {
        if (plain != crypt)
            os_memcpy(plain, crypt, len);
        rc4_skip(ctx->u.rc4.key, ctx->u.rc4.keylen,
                ctx->u.rc4.used_bytes, plain, len);
        ctx->u.rc4.used_bytes += len;
        return 0;
    }

    res = cbc_decrypt(crypt, plain, len, &ctx->u.cbc);
    if (res != CRYPT_OK) {
        wpa_printf(MSG_DEBUG, "LibTomCrypt: CBC decryption "
                "failed: %s", error_to_string(res));
        return -1;
    }

    return 0;
}


void crypto_cipher_deinit(struct crypto_cipher *ctx)
{
    if (!ctx->rc4)
        cbc_done(&ctx->u.cbc);
    os_free(ctx);
}


struct crypto_public_key {
    rsa_key rsa;
};

struct crypto_private_key {
    rsa_key rsa;
};


struct crypto_public_key * crypto_public_key_import(const u8 *key, size_t len)
{
    int res;
    struct crypto_public_key *pk;

    pk = os_zalloc(sizeof(*pk));
    if (pk == NULL)
        return NULL;

    res = rsa_import(key, len, &pk->rsa);
    if (res != CRYPT_OK) {
        wpa_printf(MSG_ERROR, "LibTomCrypt: Failed to import "
                "public key (res=%d '%s')",
                res, error_to_string(res));
        os_free(pk);
        return NULL;
    }

    if (pk->rsa.type != PK_PUBLIC) {
        wpa_printf(MSG_ERROR, "LibTomCrypt: Public key was not of "
                "correct type");
        rsa_free(&pk->rsa);
        os_free(pk);
        return NULL;
    }

    return pk;
}


struct crypto_private_key * crypto_private_key_import(const u8 *key,
        size_t len,
        const char *passwd)
{
    int res;
    struct crypto_private_key *pk;

    pk = os_zalloc(sizeof(*pk));
    if (pk == NULL)
        return NULL;

    res = rsa_import(key, len, &pk->rsa);
    if (res != CRYPT_OK) {
        wpa_printf(MSG_ERROR, "LibTomCrypt: Failed to import "
                "private key (res=%d '%s')",
                res, error_to_string(res));
        os_free(pk);
        return NULL;
    }

    if (pk->rsa.type != PK_PRIVATE) {
        wpa_printf(MSG_ERROR, "LibTomCrypt: Private key was not of "
                "correct type");
        rsa_free(&pk->rsa);
        os_free(pk);
        return NULL;
    }

    return pk;
}


struct crypto_public_key * crypto_public_key_from_cert(const u8 *buf,
        size_t len)
{
    /* No X.509 support in LibTomCrypt */
    return NULL;
}


static int pkcs1_generate_encryption_block(u8 block_type, size_t modlen,
        const u8 *in, size_t inlen,
        u8 *out, size_t *outlen)
{
    size_t ps_len;
    u8 *pos;

    /*
     * PKCS #1 v1.5, 8.1:
     *
     * EB = 00 || BT || PS || 00 || D
     * BT = 00 or 01 for private-key operation; 02 for public-key operation
     * PS = k-3-||D||; at least eight octets
     * (BT=0: PS=0x00, BT=1: PS=0xff, BT=2: PS=pseudorandom non-zero)
     * k = length of modulus in octets (modlen)
     */

    if (modlen < 12 || modlen > *outlen || inlen > modlen - 11) {
        wpa_printf(MSG_DEBUG, "PKCS #1: %s - Invalid buffer "
                "lengths (modlen=%lu outlen=%lu inlen=%lu)",
                __func__, (unsigned long) modlen,
                (unsigned long) *outlen,
                (unsigned long) inlen);
        return -1;
    }

    pos = out;
    *pos++ = 0x00;
    *pos++ = block_type; /* BT */
    ps_len = modlen - inlen - 3;
    switch (block_type) {
        case 0:
            os_memset(pos, 0x00, ps_len);
            pos += ps_len;
            break;
        case 1:
            os_memset(pos, 0xff, ps_len);
            pos += ps_len;
            break;
        case 2:
            if (os_get_random(pos, ps_len) < 0) {
                wpa_printf(MSG_DEBUG, "PKCS #1: %s - Failed to get "
                        "random data for PS", __func__);
                return -1;
            }
            while (ps_len--) {
                if (*pos == 0x00)
                    *pos = 0x01;
                pos++;
            }
            break;
        default:
            wpa_printf(MSG_DEBUG, "PKCS #1: %s - Unsupported block type "
                    "%d", __func__, block_type);
            return -1;
    }
    *pos++ = 0x00;
    os_memcpy(pos, in, inlen); /* D */

    return 0;
}


static int crypto_rsa_encrypt_pkcs1(int block_type, rsa_key *key, int key_type,
        const u8 *in, size_t inlen,
        u8 *out, size_t *outlen)
{
    unsigned long len, modlen;
    int res;

    modlen = mp_unsigned_bin_size(key->N);

    if (pkcs1_generate_encryption_block(block_type, modlen, in, inlen,
                out, outlen) < 0)
        return -1;

    len = *outlen;
    res = rsa_exptmod(out, modlen, out, &len, key_type, key);
    if (res != CRYPT_OK) {
        wpa_printf(MSG_DEBUG, "LibTomCrypt: rsa_exptmod failed: %s",
                error_to_string(res));
        return -1;
    }
    *outlen = len;

    return 0;
}


int crypto_public_key_encrypt_pkcs1_v15(struct crypto_public_key *key,
        const u8 *in, size_t inlen,
        u8 *out, size_t *outlen)
{
    return crypto_rsa_encrypt_pkcs1(2, &key->rsa, PK_PUBLIC, in, inlen,
            out, outlen);
}


int crypto_private_key_sign_pkcs1(struct crypto_private_key *key,
        const u8 *in, size_t inlen,
        u8 *out, size_t *outlen)
{
    return crypto_rsa_encrypt_pkcs1(1, &key->rsa, PK_PRIVATE, in, inlen,
            out, outlen);
}


void crypto_public_key_free(struct crypto_public_key *key)
{
    if (key) {
        rsa_free(&key->rsa);
        os_free(key);
    }
}


void crypto_private_key_free(struct crypto_private_key *key)
{
    if (key) {
        rsa_free(&key->rsa);
        os_free(key);
    }
}


int crypto_public_key_decrypt_pkcs1(struct crypto_public_key *key,
        const u8 *crypt, size_t crypt_len,
        u8 *plain, size_t *plain_len)
{
    int res;
    unsigned long len;
    u8 *pos;

    len = *plain_len;
    res = rsa_exptmod(crypt, crypt_len, plain, &len, PK_PUBLIC,
            &key->rsa);
    if (res != CRYPT_OK) {
        wpa_printf(MSG_DEBUG, "LibTomCrypt: rsa_exptmod failed: %s",
                error_to_string(res));
        return -1;
    }

    /*
     * PKCS #1 v1.5, 8.1:
     *
     * EB = 00 || BT || PS || 00 || D
     * BT = 01
     * PS = k-3-||D|| times FF
     * k = length of modulus in octets
     */

    if (len < 3 + 8 + 16 /* min hash len */ ||
            plain[0] != 0x00 || plain[1] != 0x01 || plain[2] != 0xff) {
        wpa_printf(MSG_INFO, "LibTomCrypt: Invalid signature EB "
                "structure");
        return -1;
    }

    pos = plain + 3;
    while (pos < plain + len && *pos == 0xff)
        pos++;
    if (pos - plain - 2 < 8) {
        /* PKCS #1 v1.5, 8.1: At least eight octets long PS */
        wpa_printf(MSG_INFO, "LibTomCrypt: Too short signature "
                "padding");
        return -1;
    }

    if (pos + 16 /* min hash len */ >= plain + len || *pos != 0x00) {
        wpa_printf(MSG_INFO, "LibTomCrypt: Invalid signature EB "
                "structure (2)");
        return -1;
    }
    pos++;
    len -= pos - plain;

    /* Strip PKCS #1 header */
    os_memmove(plain, pos, len);
    *plain_len = len;

    return 0;
}


int crypto_global_init(void)
{
    ltc_mp = tfm_desc;
    /* TODO: only register algorithms that are really needed */
    if (register_hash(&md4_desc) < 0 ||
            register_hash(&md5_desc) < 0 ||
            register_hash(&sha1_desc) < 0 ||
            register_cipher(&aes_desc) < 0 ||
            register_cipher(&des_desc) < 0 ||
            register_cipher(&des3_desc) < 0) {
        wpa_printf(MSG_ERROR, "TLSv1: Failed to register "
                "hash/cipher functions");
        return -1;
    }

    return 0;
}


void crypto_global_deinit(void)
{
}


#ifdef CONFIG_MODEXP

int crypto_mod_exp(const u8 *base, size_t base_len,
        const u8 *power, size_t power_len,
        const u8 *modulus, size_t modulus_len,
        u8 *result, size_t *result_len)
{
    void *b, *p, *m, *r;

    if (mp_init_multi(&b, &p, &m, &r, NULL) != CRYPT_OK)
        return -1;

    if (mp_read_unsigned_bin(b, (u8 *) base, base_len) != CRYPT_OK ||
            mp_read_unsigned_bin(p, (u8 *) power, power_len) != CRYPT_OK ||
            mp_read_unsigned_bin(m, (u8 *) modulus, modulus_len) != CRYPT_OK)
        goto fail;

    if (mp_exptmod(b, p, m, r) != CRYPT_OK)
        goto fail;

    *result_len = mp_unsigned_bin_size(r);
    if (mp_to_unsigned_bin(r, result) != CRYPT_OK)
        goto fail;

    mp_clear_multi(b, p, m, r, NULL);
    return 0;

fail:
    mp_clear_multi(b, p, m, r, NULL);
    return -1;
}

#endif /* CONFIG_MODEXP */
